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1.
J Environ Radioact ; 217: 106213, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32217245

RESUMO

Vertical and horizontal distributions are fundamental for sampling and in-situ gamma spectrum measurement strategies. The distributions of 137Cs were investigated for paved surfaces affected by the Fukusima Dai-ichi Nuclear Power Plant accident. Additionally, the effects of the distributions on the measurement uncertainties of in-situ spectrometry were evaluated. Relaxation mass depth, representing the depth profile of 137Cs, was estimated to be less than 0.23 g cm-2. Variation in the relaxation mass depth, of 0.1-0.23 g cm-2, led to a minor error (less than 5%) in the spectral analysis of the137Cs inventory (activity per unit area, kBq m-2). The 137Cs inventory, within a 20 × 20 m square of 400 cells each measuring 1 m2, showed an uneven distribution with large variation; coefficient of variation ranged from 54 to 136% of geometric average inventory of 424 kBq m-2. Increasing the grid size decreased 137Cs inventory variation among cells, revealing the relationship between instrument field of view and the spatial uncertainty of the results of in-situ gamma spectrometry.


Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Radioisótopos de Césio , Japão , Centrais Nucleares , Poluentes Radioativos do Solo , Espectrometria gama
2.
J Environ Radioact ; 216: 106180, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32217197

RESUMO

The measurement of radiotracers is recognized as a major tool for the investigation and characterization of submarine groundwater discharges, while the use of underwater gamma-ray spectrometry has been proved a robust solution for the qualitative and quantitative determination of radionuclides in the aquatic environment. The capability of online continuous monitoring of submarine springs by means of gamma-ray spectrometry for direct estimation of SGD velocity and discharge is presented. The quantification of SGD flux rate is based on radon progenies time-series provided by two spectrometers placed above the seabed and near the water surface respectively, coupled with water level and meteorological data. The proposed methodology has been applied for a 5-month period in a coastal karstic system where multiple submarine springs occur at Anavalos-Kiveri, Greece. The estimated flux rates derived from the measured activities revealed significant SGD temporal variations with the mean discharge of 12 m3 s-1 being compatible with previous measurements. The advantages and limitations of direct SGD estimation via underwater gamma-ray monitoring are also discussed.


Assuntos
Monitoramento de Radiação , Espectrometria gama , Monitoramento Ambiental , Grécia , Água Subterrânea , Água do Mar , Movimentos da Água , Poluentes Radioativos da Água
3.
J Environ Radioact ; 216: 106181, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32056789

RESUMO

The methodology for determination of 241Pu in soils of the main test sites of the Semipalatinsk Test Site (STS) has been developed. The results of 241Am and 241Pu activity determination in soil samples sampled at the main testing sites of the STS are presented. 241Pu/241Am activity ratio is calculated. In most cases, on local sites, 241Pu/241Am activity ratio is in a rather narrow range, which makes it possible to estimate 241Pu activity based on the results of 241Am gamma-spectrometric analysis. The accuracy of 241Pu activity estimation using this method will be about 50%, which is quite enough in most cases.


Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo/análise , Amerício , Cazaquistão , Plutônio , Solo , Espectrometria gama
4.
J Environ Radioact ; 216: 106187, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32056791

RESUMO

The Comprehensive Nuclear-Test-Ban Treaty is supported by a global network of monitoring stations that perform high-resolution gamma-spectrometry on air filter samples. The UK CTBT Radionuclide Laboratory has utilised cosmic veto systems to improve the sensitivity of measurements since 2010. During this study, a second detector system (with a cosmic veto) was deployed at the CTBT IMS station RN67, alongside the standard detector. This is an incredibly remote IMS station on the island of St Helena in the South Atlantic. A duplicate system was also tested at AWE to benchmark the remote systems performance. The cosmic veto system improved detection sensitivities by up to 10% across a range of radionuclides. As a system to re-measure samples 7 days after the primary measurement, detection sensitivities were improved by an order of magnitude, allowing a potentially crucial confirmation of signatures when timely transport to a laboratory is not feasible. Utilising the second detector in coincidence with the primary detector system (which would require reengineering of the shield), sensitivity improvements of up to two orders of magnitude can be achieved. These improvements are maintained even when the measurement takes place without any decay, potentially allowing a highly sensitive treaty measurement within 2 h of the end of collection.


Assuntos
Monitoramento de Radiação , Radioisótopos/análise , Poluentes Radioativos do Ar , Reprodutibilidade dos Testes , Espectrometria gama
5.
Environ Geochem Health ; 42(2): 513-529, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31363944

RESUMO

The work presents the historical evolution, objectives, goals, concepts, chemical and radiometric methods, results and conclusions for salt waters and natural peloids used in pelotherapy. This study assesses chemical composition, natural radioactivity concentrations and the radiological hazard in peloid and salt water samples, from ten places in the Techirghiol Lake from Romania. Pelotherapy is a very important procedure, and thus, the materials used for this purpose must be well characterized to guaranty safety use. Concentrations of elements such as Sr, Ba, Mn, Fe, Sb, Zn, Cu, Pb, Ti, Ni, Cr, As have been measured using ICP-OES analytical technique. The natural radionuclides such as 238U, 226Ra, 232Th and 40K have been determined by gamma-ray spectrometry. The average activity concentrations were of 0.48 ± 0.10 Bq/kg for 238U, 0.60 ± 0.10 Bq/kg for 226Ra, 0.30 ± 0.08 Bq/kg for 232Th and 17.5 ± 1.3 Bq/kg for 40K for salt water samples. Also, the mean activity concentrations for peloids were: 5.70 ± 1.00 Bq/kg for 238U, 6.85 ± 1.60 Bq/kg for 232Th, 15.3 ± 3.7 Bq/kg for 226Ra and 95.8 ± 5.5 Bq/kg for 40K. The results from this study contribute to the identification of possible contaminants in the salt water and peloid, and their association with the potential ecological and human health risk. In this context, of using salt water and peloid in a relatively long treatment period, several radiological indices have been calculated, to determine if the radionuclide's content can be also harmful to human health. The assessment indicates that humans are not exposed to concentrations of metal contaminants higher than the international recommended values.


Assuntos
Radiação de Fundo , Lagos/análise , Lagos/química , Terapia por Lama , Radioisótopos/análise , Raios gama , Sedimentos Geológicos/análise , Humanos , Concentração de Íons de Hidrogênio , Metais/análise , Radioisótopos de Potássio/análise , Monitoramento de Radiação/métodos , Rádio (Elemento)/análise , Romênia , Salinidade , Espectrometria gama , Temperatura , Tório/análise , Urânio/análise
6.
J Environ Radioact ; 213: 106103, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31751802

RESUMO

The paper presents the results of 90Sr/137Cs isotopic ratios in the soil surface layer in the venues of surface and atmospheric nuclear tests at the territory of the «Experimental Field ¼â€¯site of the Semipalatinsk Test Site. One of the main factors in the radiation impact of a nuclear explosion on the environment is the decay of fission products. The determination of 137Cs activity in soil is carried out by accurate, rapid and sufficiently cheap gamma-spectrometric method, while the existing methods of determining 90Sr activity are quite problematic: they either have sufficiently high detection limits or are time-consuming. As an alternative method, 90Sr activity can be determined using its correlation dependence with 137Cs activity. According to the literature, each test has its own fission product ratio, depending on the nuclear charge. As a result of the conducted research it was revealed that one epicenter is located at the technical site P-1, the ratio of 90Sr/137Cs is equal to 4,8; at the technical site P-3 - 2 epicenters, the ratio of 90Sr/137Cs is equal to 0,8 and 0,9; at the technical site P-5 - 6 epicenters, the ratio of 90Sr/137Cs is in the range of 0,9-2,1; at the technical sites P-2, P-7 - 19 epicenters, the ratio of 90Sr/137Cs is in the range of 0,6-2,1. It is assumed that the differences in the value of fission product ratios are due to different types and capacities of nuclear charges, as well as different explosion altitudes. The obtained ratios allow to calculate 90Sr by 137Cs activity in soil of the epicentral zones at the territory of the «Experimental Field ¼â€¯testing site by the computational method.


Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo/análise , Radioisótopos de Césio , Solo , Espectrometria gama , Estrôncio , Radioisótopos de Estrôncio
7.
Environ Pollut ; 258: 113825, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31874441

RESUMO

The establishment of a screening index would be a powerful tool to decide whether abandoned uranium mining areas should be rehabilitated or decommissioned. Thus, in this work we established a radiological index which uses the activity concentrations of different groups of gamma emitters from the natural radioactive series of 238U, 235U, and 232Th, as well as 40K and 137Cs. These activity concentrations were calculated by using the absorbed gamma radiation dose value of 175 nGy h-1 specified in the U.S. Code of Federal Regulations. We studied our index in an abandoned uranium mining area in Salamanca, Western Spain, and found that the most influential factors in this area were the presence of organic matter in the soil and the possible effect that plants and fungi may have on the retention of these aforementioned radionuclides. In addition, the results showed that contaminants are migrating in an easterly direction in line with the prevailing wind direction and we were able to identify areas in which the radiological risk is likely high. The mean effective dose rate was 2.51 ± 0.98 mSv y-1 which was equivalent to the levels obtained in previous works.


Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo , Urânio , Mineração , Espanha , Espectrometria gama , Tório
8.
Environ Monit Assess ; 191(11): 660, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31646407

RESUMO

This study makes a first attempt at a detailed estimation of the background radioactivity level and its distribution at the Sinop nuclear power plant site. The activity concentration levels of 226Ra, 232Th, 40K and 137Cs radionuclides in soil samples collected from 88 locations around Sinop Province, Turkey, in November 2016, were measured using gamma spectrometry. The distributions of radionuclide levels obtained from the results were evaluated using a geostatistical method, and the estimated radiation levels were determined using the ordinary kriging (OK) method, which is the best linear unbiased estimator (BLUE) for unmeasured points. Estimates of distribution results were evaluated using cross-validation diagrams, and it was shown that the OK method could predict radiological distributions for appropriate criteria. Finally, using the kriging parameters, distributions of radiation levels for the entire work area were mapped at a spatial resolution of 100 × 100 m2. These maps show that the natural radionuclides (226Ra, 232Th and 40K) are distributed at higher levels to the southeast of Sinop than in the other regions, and the activity of an artificial radionuclide (137Cs) is high in the interior and northern sections.


Assuntos
Elementos Radioativos/análise , Centrais Nucleares/estatística & dados numéricos , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Análise Espacial , Radiação de Fundo , Radioisótopos de Césio/análise , Radioisótopos de Potássio/análise , Rádio (Elemento)/análise , Espectrometria gama/métodos , Tório/análise , Turquia
9.
Appl Radiat Isot ; 154: 108853, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31493660

RESUMO

Currently, there is no imaging procedure for radionuclide therapy utilizing Erbium-169 (Er-169). We have recently published the first post-radiosynovectomy imaging of Er-169 citrate in a case report (Farahati et al., 2017). In this study, we performed in-vitro and in-vivo studies to evaluate the feasibility to assess the distribution of Er-169 citrate after radiosynovectomy in fourteen patients with seventeen affected joints treated for refractory chronic synovitis. Post-radiosynovectomy imaging revealed the feasibility of post-radiosynovectomy detection and distribution utilizing Er-169 citrate in all cases. However, additional in-vitro studies including in-vitro imaging, gamma spectrometry and analysis of half-life indicated that emitted gamma-rays of the Ytterbium-169 in the radiopharmaceutical together with bremsstrahlung induced by Er-169 are the imaging source of emitted counts. Post-radiosynovectomy imaging utilizing Er-169 citrate is feasible and should be implemented in the guidelines for theranostics for quality control, patient safety and therapy monitoring.


Assuntos
Érbio/uso terapêutico , Radioisótopos/uso terapêutico , Compostos Radiofarmacêuticos/uso terapêutico , Sinovectomia/métodos , Sinovite/diagnóstico por imagem , Sinovite/radioterapia , Adulto , Idoso , Artrite Reumatoide/diagnóstico por imagem , Artrite Reumatoide/radioterapia , Doença Crônica , Ácido Cítrico/uso terapêutico , Estudos de Viabilidade , Feminino , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Osteoartrite/diagnóstico por imagem , Osteoartrite/radioterapia , Espectrometria gama
10.
J Environ Radioact ; 208-209: 106016, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31325733

RESUMO

Theoretical and experimental studies have shown that activity concentrations of fallout radionuclides (such as 137Cs and excess 210Pb) decrease with particles size in aqueous suspensions. This paper is aimed at reviewing the theoretical fundamentals for granulometric speciation of radionuclides, and at exploring its practical use in the analytical context of gamma spectrometry for the radiometric dating of recent sediments, with view to: i) improving the detection of 137Cs (since its use as independent chronostratigraphic mark is challenging in the southern hemisphere because its low fallout rate), ii) supporting refined CIC models and normalization techniques in 210Pb-based radiogeochronologies. The work uses surface sediments sampled from the Tinto Estuary (SW Spain), affected by mining and phosphate-fertilizer industries, and from the Ankobra Estuary (Ghana), affected by intensive artisanal gold-mining. Granulometric classes have been separated by a sieving column with decreasing mesh sizes and the obtained cumulative percentage of mass mathematically described by a Rosin-Rammler particle-size distribution. The target radionuclides for gamma spectrometry were 210Pb, 226Ra and137Cs, complemented with 40K, 234Th and 228Ra. Results revealed that, far from ideal experiments, under actual environmental conditions the increase in activity concentrations with decreasing particle sizes is too moderate, and in general they are affected by larger counting uncertainties due to the small available amount of mass. Indeed, there was no correlation between grain-size and 137Cs concentrations (p = 0.25), and similarly for excess 210Pb (p = 0.53). No effect of the organic matter content was observed in 137Cs (p = 0.58) and excess 210Pb (p = 0.85) concentrations. Present results pose some concerns to the general use of granulometric speciation in the context of gamma spectrometry for supporting the radiometric dating of recent sediments. A detailed discussion on the use of normalization methods is also presented.


Assuntos
Sedimentos Geológicos/química , Monitoramento de Radiação , Datação Radiométrica/métodos , Poluentes Radioativos da Água/análise , Gana , Mineração , Espanha , Espectrometria gama
11.
Forensic Sci Int ; 302: 109867, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284202

RESUMO

In preparing to respond to security incidents involving radioactive material, States should consider how they might address the unique challenge of analysing forensic evidence contaminated with these materials. In the case of DNA evidence, previous research has suggested that commercial forensic DNA extraction kits may be able to remove radioactive contamination from biological samples. If viable, this would allow the extraction and decontamination of biological samples to be undertaken in a laboratory equipped to handle radioactive material, with the subsequent quantification and profiling of extracted DNA performed in a conventional forensics laboratory. In order to inform the development of an operational capability, this study sought to expand upon previous work to provide a more comprehensive quantitative assessment of the efficacy of commercial DNA extraction kits for the removal of radionuclide contamination from biological samples and the quality of the resultant DNA profiles. Three commercial DNA extraction kits were tested for their ability to remove contaminating radionuclides. Two of these kits proved more effective at removing radionuclide contamination and produced DNA extracts of higher quality. Under all conditions tested in this study, decontamination efficiency was sufficient to allow the release of samples to a forensic laboratory. However, consistent with a prudent approach to radiation safety it is recommended that all samples be screened by gamma spectrometry prior to their release to a forensic laboratory in order to verify decontamination.


Assuntos
Impressões Digitais de DNA , DNA/isolamento & purificação , DNA/efeitos da radiação , Descontaminação , Radioisótopos , Manejo de Espécimes/instrumentação , Bombas (Dispositivos Explosivos) , Contaminação de Equipamentos , Genética Forense , Humanos , Masculino , Espectrometria gama
12.
Radiat Prot Dosimetry ; 184(3-4): 290-293, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31297520

RESUMO

Elevated levels of natural background radiation due to scattered patches of monazite sand around the beaches of Mangalore, India, have been reported earlier. A comparative study of gamma dose rates was performed in both normal background and high natural background radiation areas around Mangalore using different types of portable gamma dosimeters. In addition to this, gamma-ray energy spectra were acquired, in situ, using a NaI(Tl) based portable gamma spectrometer. Soil and sand samples were collected for laboratory analysis with HPGe detectors. Measurements were carried out during the years 2016-18 revealed that in majority of the locations the gamma dose rates were similar to the normal background regions, whereas, in certain locations the dose rates were higher with values up to 530 nSv/h.


Assuntos
Radiação de Fundo , Raios gama , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Espectrometria gama/métodos , Humanos , Índia , Metais Terras Raras , Doses de Radiação
13.
Appl Radiat Isot ; 151: 30-38, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31158703

RESUMO

Sources of background and background variation in a BEGe type HPGe detector located in a surface laboratory were identified. Different strategies for background reduction were applied. A cosmic veto was installed, and optimised using a digital acquisition system in list-mode with time-stamped data. This resulted in the reduction of total background by a factor of 1.4. Thermal and fast neutron fluxes were also calculated. The radon induced background component and its variation were significantly reduced.


Assuntos
Poluentes Radioativos do Ar/análise , Monitoramento de Radiação/métodos , Radônio/análise , Espectrometria gama/métodos
14.
Appl Radiat Isot ; 151: 207-216, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31203051

RESUMO

In this study, average radon flux distribution in the Rize province (Turkey) was estimated by the artificial neural networks (ANN) method. For this purpose, terrestrial gamma dose rate (TGDR), which is defined as an important proxy in determining radon flux distribution, was used. Input parameters that were used for ANN were the natural radionuclide (238U, 232Th and 40K) activity values in soil samples taken from 64 stations in Rize Province, data from ambient gamma dose rates (AGDR) directly affecting the distribution of radon flux and data of geographical coordinates. Randomly chosen 42 stations were used for ANN training and data from 22 stations were used for testing the ANN model. Performance test results gave a Pearson's r value of 0.60 (p < 0.001) and RMSE of 0.296. The area that was used for the model was divided into grids of 100 m by 100 m and a spatial distribution map was composed by using ANN predicted radon flux rates at grid nodes, whereby natural radionuclide values and Ordinary Kriging predicted values of external gamma dose rates were used for composing the map.


Assuntos
Redes Neurais de Computação , Radônio/análise , Poluentes Radioativos do Solo/análise , Espectrometria gama/métodos , Turquia
15.
Appl Radiat Isot ; 151: 129-139, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31177070

RESUMO

Ramlet Homayyer area is located in the southwestern part of Sinai Peninsula, Egypt, to the east of Abu-Zeneima city, located on the eastern coast of Gulf of Suez, Red Sea. The Paleozoic succession in the study area (up to 300 m thick) overlies the basement complex and is covered by basaltic sheets. The lithologic nature of the Paleozoic rocks played a very important role in the localization of various mineralizations (e.g. Mn, Fe, Cu, REEs, Th … etc.) In the present study of Ramlet Homayyer area, ground spectral gamma-ray survey was conducted along N-S profiles, equally-spaced, with lengths of about 2.5 km, and the total area equals about 10 km2. The measurements were conducted using a portable gamma-ray spectrometer, model GS-512. The examination of the total-count (T.C.) radiometric contour map shows that the radioactivity values vary widely from 3.4 Ur to 101.3 Ur. The potassium (K) content in Ramlet Homayyer area ranges from 1.2% to 16.0%. The equivalent thorium (eTh) content in the study area has a maximum value reaching about 68.9 ppm. The equivalent uranium (eU) content attains its maximum value reaching about 84.0 ppm. Factor analysis technique, which provides a way of thinking about radiospectrometric elements and ratio interrelationships alltogether was carried out. The application of factor analysis technique, helped to delineate the zones of high concentrations of eU, eTh and K separately, where the first factor (F1) can delineate high eU zones, (F2) high eTh zones and (F3) high K zones. The radiometric lithologic mapping was conducted for the whole area, by testing the homogeneity of all measurements recorded indicates that the distribution of the radioactivity all over the area is not homogeneous. This indicates that the lithological cover of the study area cannot be considered as one lithologic unit, but contains different types of rock units. Each Interpreted radiometric lithologic units (IRLU) is corresponding to one geomorphological mass or features. As a result of the ground radiometric survey of the study area, chemical analyses for some selected samples were taken and conducted from the anomalous zones at G. Homayyer, G. Ghorabi and Khameila areas. These analyses showed presence of concentrations of uranium up to 147 ppm, 58 ppm, 52 ppm in addition to trace elements with high concentrations of some elements as: Y, Cr, W, Sr and Ag, which gives 6819,768,314,561 and15 ppm respectively.


Assuntos
Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Espectrometria gama/métodos , Egito , Seguimentos , Imagens de Satélites , Inquéritos e Questionários
16.
Appl Radiat Isot ; 149: 142-151, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31063963

RESUMO

Gamma-ray spectrometry is applied to estimate equivalent uranium (eU), equivalent thorium (eTh), and K% of 748 rock samples collected from Syrian territory. The spectrometry results are used to evaluate and map the radioactive heat production (HP) of Syria. A new approach involving the multifractal technique with the concentration-number model (CN) and log-log plots was originally proposed and hence applied in this paper to map the distribution of uranium concentration and HP of Syria. This approach helps us to differentiate different eU and HP ranges related to different litho-types. The advantages of proposing and applying the fractal technique are that the boundaries of the distinguished radioactive ranges of eU and HP coincide well with the lithological boundaries, which gives this technique superiority over other traditional statistical methods. The fractal CN model with the use of log-log plots proves its efficacy in differentiating between several eU and HP populations that are related directly to the geology of Syrian territory. The fractal model shows four threshold break points corresponding to uranium concentrations of 3.1, 7.38, 16.6, and 28.8 ppm and an HP of 0.715, 1.86, 3.63, and 6.26 µW/m3, respectively. The highest HP ranges are mainly related to the phosphatic deposits, characterized by the highest uranium content.


Assuntos
Temperatura Alta , Monitoramento de Radiação/métodos , Geologia , Poluentes Radioativos do Solo/análise , Espectrometria gama/métodos , Síria , Tório/análise , Urânio/análise
17.
Health Phys ; 117(4): 449-456, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31124830

RESUMO

Timely achievement of uranium series' secular equilibrium is not always feasible. Our objective is to mathematically justify methods for early uranium series gamma spectroscopy measurements that can accurately predict naturally occurring radioactive material equilibrium activities long before equilibrium is established. It was believed that, regardless of prior Rn escape, after sealing a sample for a few hours the activities of Rn, Ra, and U could theoretically be determined with a single measurement of both Pb and Bi. However, when accounting for error, this theory did not work as expected (CV = 14.0 in Ra simulation). A similar approach published by Li et al. in 2015 proved to be much more reliable with the error considered, using Pb activities measured at two different times gave significantly improved results when tested the same way (CV = 0.29 in Ra simulation). Because both Pb and Bi activities are typically available when using gamma spectrometry, we combine these approaches and further increased the accuracy of the calculated activities (CV = 0.21 in Ra simulation).


Assuntos
Radiação de Fundo , Monitoramento de Radiação/métodos , Rádio (Elemento)/análise , Espectrometria gama/métodos , Tório/análise , Urânio/análise , Humanos
18.
Health Phys ; 117(3): 278-282, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31124835

RESUMO

Military historical artifacts found in museum displays and storage locations were analyzed for their Ra and Rn progeny activities to determine the fraction of Rn lost to the environment. Gamma-ray spectroscopy using high-purity germanium detectors was used to determine Ra activity and infer Rn activity based on Pb and Bi. Analyses were conducted without affecting the structural integrity of the artifacts. Ra was measured directly after correction for solid angle and finite sample-detector distance. Although Rn can be similarly analyzed, the collection in charcoal of Rn off-gassed from the artifact after the establishment of secular equilibrium was preferable. Rn off-gassing rates vary greatly between the six devices studied, with a maximum off-gassing rate of 1,850 ± 50 Bq h. Large variations in off-gassing rate were also observed between an additional 30 nominally identical dials, with a mean and standard deviation of 7.7 ± 7.1 Bq h. The work is not predictive of airborne Rn activity within museums, where building size and ventilation are significant and unique to each location. However, the significant off-gassing rates and their large variation suggest that Rn activities may be elevated in enclosed locations, such as aircraft cockpits and storage facilities.


Assuntos
Poluentes Radioativos do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Materiais de Construção/análise , Monitoramento de Radiação/métodos , Rádio (Elemento)/análise , Radônio/análise , Espectrometria gama/instrumentação , Artefatos , Humanos , Instalações Militares , Espectrometria gama/métodos , Ventilação
19.
Radiat Prot Dosimetry ; 184(3-4): 359-362, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31089715

RESUMO

Uranium, thorium and potassium are the most abundant naturally occurring radioactive materials (NORMs) found in soils and other environmental media including foodstuffs. Since the human exposures to NORMs is an unavoidable phenomenon, in such a way that they can easily find their way to human being via food chain, detailed knowledge on their presence in foodstuffs is necessary to assess the radiation dose to the population. Thus, the present study concerns the assessment of natural radioactivity in maize, a staple foodstuff for Nigerian, via HPGe gamma-ray spectrometry. Activity concentrations (Bq/kg) in the maize samples were found to be in the range of 6.1 ± 0.6-8.2 ± 1.3, 2.2 ± 0.4-5.1 ± 0.7 and 288 ± 16-401 ± 24 for 226Ra, 232Th and 40K, respectively. Measured data for 226Ra and 232Th show below the world average values of 67 Bq/kg and 82 Bq/kg, respectively, while the activity of 40K exceeds the global average of 310 Bq/kg. The annual effective dose via the maize consumption was found to be far below the UNSCEAR recommended ingestion dose limit of 290 µSv/y, and the estimated lifetime cancer risk show lower than the ICRP (1991) cancer risk factor of 2.5 × 10-3 based on the additional annual dose limit of 1 mSv for general public, thus pose no adverse health risk to the Nigerian populace.


Assuntos
Radiação de Fundo , Radioisótopos de Potássio/análise , Monitoramento de Radiação/métodos , Rádio (Elemento)/análise , Poluentes Radioativos do Solo/análise , Tório/análise , Zea mays/metabolismo , Ingestão de Alimentos , Nigéria , Doses de Radiação , Espectrometria gama , Zea mays/efeitos da radiação
20.
Radiat Prot Dosimetry ; 184(3-4): 347-350, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31089716

RESUMO

A car-borne survey of air dose rate measurements was performed yearly from 2011 to 2013 to determine the levels of environmental radiation in Gunma prefecture after the Fukushima Daiichi Nuclear Power Plant accident in 2011. The results revealed that the average ambient doses in each year were 85.3 ± 34.1 nGy/h in 2011, 60.3 ± 19.9 nGy/h in 2012, and 43.5 ± 15.1 nGy/h in 2013. The ambient dose rate in 2011, which was about three times higher than the average of 27.0 ± 7.1 nGy/h in 1998, was still in safety level considering the public health, and the ambient dose rate subsequently decreased in 2013 to approximately half the 2011 level. A contour map of the ambient dose rate showed relatively higher levels in the northern and western parts of the prefecture, with relatively lower levels toward the eastern and southern parts.


Assuntos
Poluentes Radioativos do Ar/análise , Automóveis , Poluição Ambiental/análise , Acidente Nuclear de Fukushima , Monitoramento de Radiação/métodos , Humanos , Japão , Centrais Nucleares , Doses de Radiação , Espectrometria gama , Inquéritos e Questionários
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